If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

A8-3500M + Radeon HD 6650M: make it cool?

06-08-2012, 10:07 AM

Ok, so I've got an Acer AS5560G-SB448 with A8-3500M + Radeon HD 6620G.
It is running pretty well, but seems a touch on the warm side, idles at about 60-65^C. Seems a little high for a 35 watt part with the fan blowing about 1/3 to 1/2 power....

power management method is set to profile, profile is set to low. Doesn't seem to make any difference from profile set to default. Setting the method to "dynpm" crashes the kernel in a very bad way. There is zero problem with performance, my GPU needs are very low, and compositing is unbelievably fluid.

Now questions about this processors specifications and what I can expect to be able to do with it;

1) CPU cores idle at 800 MHz, and max out at 1500 MHz. Now I know that the thing is *supposed* to "turbocore" up to 2400 MHz, but this doesn't seem to actually happen. Any way to make this work? Any way to get the thing to scale down LOWER than 800 MHz? 800 MHz seems a little higher than it needs to be. Any way to shut down excess cores when not needed?
2) Voltages... they scaling properly for CPU and GPU? Any way to monitor these? Any way to check the GPU frequency?

Objective here is to damn the performance, force it to use as little power as possible. Any suggestions?

Comment

Read topics on this forum and check tests from phoronix, you will see that OSS drivers use a lot more power than fglrx drivers for the same usage.
You just won't be able to do a lot about this whatever low profile or not you set. (and dynpm is not really stable on a lot of pc)

And thank you for your concern, but I "waste my time" as I see fit

Comment

Read topics on this forum and check tests from phoronix, you will see that OSS drivers use a lot more power than fglrx drivers for the same usage.
You just won't be able to do a lot about this whatever low profile or not you set. (and dynpm is not really stable on a lot of pc)

And thank you for your concern, but I "waste my time" as I see fit

Go waste your time OUT OF MY THREAD!!!!

Comment

1) CPU cores idle at 800 MHz, and max out at 1500 MHz. Now I know that the thing is *supposed* to "turbocore" up to 2400 MHz, but this doesn't seem to actually happen. Any way to make this work? Any way to get the thing to scale down LOWER than 800 MHz? 800 MHz seems a little higher than it needs to be. Any way to shut down excess cores when not needed?

2) Voltages... they scaling properly for CPU and GPU? Any way to monitor these? Any way to check the GPU frequency?

Don't have much info on the CPU side -- in theory everything needed for CPU power management is enabled in the system BIOS but we have seen some reports recently where CPU power draw seems to be higher with the open drivers. Not sure why that is yet.

On the GPU side, IIRC agd5f said that we were not reducing GPU voltages on APU parts yet.

Comment

It appears that a fair amount of undervolting is possible with Llano. However this helps more with the load consumption than with idle (because idle parts are typically gated off). On Linux you will probably need to decompile your ACPI DSDT and adjust the voltage in the various power states. Then compile it and pass to kernel via ACPI_CUSTOM_DSDT option. Reportedly 0.2-0.3V can be shaved off on Llano before the system becomes unstable.

Some general information on hacking your DSDT can be found at gentoo-wiki.com.

Comment

Don't have much info on the CPU side -- in theory everything needed for CPU power management is enabled in the system BIOS but we have seen some reports recently where CPU power draw seems to be higher with the open drivers. Not sure why that is yet.

On the GPU side, IIRC agd5f said that we were not reducing GPU voltages on APU parts yet.

Guess that would explain it then... I don't suppose you've got an ETA for when that may be implemented?
Is there any way I could go about forcing the voltage down manually?

Comment

It appears that a fair amount of undervolting is possible with Llano. However this helps more with the load consumption than with idle (because idle parts are typically gated off). On Linux you will probably need to decompile your ACPI DSDT and adjust the voltage in the various power states. Then compile it and pass to kernel via ACPI_CUSTOM_DSDT option. Reportedly 0.2-0.3V can be shaved off on Llano before the system becomes unstable.

Some general information on hacking your DSDT can be found at gentoo-wiki.com.

Needs to have debugfs enabled in the kernel. If you use an external monitor, then the memory clock is fixed... this is on a dedicated AMD 6970M with the latest radeon driver
You can change the clocks by choosing a profile: